Note on the analysis of moisture-depth curves obtained by the hot-air method for the determination of soil moisture diffusivity

Diffusivities of undisturbed soil samples can be determined with the so-called hot-air method. Several graphical and numerical methods exist for the analysis of the moisture vs. depth curves obtained with this method. In this paper the method of Van den Berg and Louters is critically reviewed and some modifications are suggested. Moreover, an implicit finite difference approach to the problem suggests that near the drying surface of the soil sample, diffusivity values are higher than under natural circumstances as a result of the treatment with hot air.